Implants such as stents and occlusive coils have been used in patients for a wide variety of reasons. One of the most common “stenting” procedures is carried out in connection with the treatment of atherosclerosis, a disease which results in a narrowing and stenosis of body lumens, such as the coronary arteries. At the site of the narrowing (i.e., the site of a lesion) a balloon is typically dilatated in an angioplasty procedure to open the vessel. A stent is set in apposition to the interior surface of the lumen in order to help maintain an open passageway. This result may be affected by means of scaffolding support alone or by virtue of the presence of one or more drugs carried by the prosthesis to aid in the prevention of restenosis.
Various stent designs exist and are in use today, but self-expandable and balloon-expandable stent systems and their related deployment techniques are now predominant. Examples of currently available self-expandable stents are the Magic WALLSTENT® stents and Radius stents (Boston Scientific). The Cypher® stent (Cordis Corporation) is a commonly used balloon-expandable stent. Additional self-expanding stent background is presented in: “An Overview of Superelastic Stent Design,” Min. Invas Ther & Allied Technol 822: 9(3/4) 235-246, “A Survey of Stent Designs,” Min. Invas Ther & Allied Technol 822: 11(4) 137-147, and “Coronary Artery Stents: Design and Biologic Considerations,” Cardiology Special Edition, 823: 9(2) 9-14, “Clinical and Angiographic Efficacy of a Self-Expanding Stent” Am Heart J 823: 145(5) 868-874.
Because self-expanding prosthetic devices need not be set over a balloon (as with balloon-expandable designs), self-expanding stent delivery systems can be designed to a relatively smaller outer diameter than their balloon-expandable counterparts. As such, self-expanding stents may be better suited to reach the smallest vasculature or achieve access in more difficult cases. To realize such benefits, however, there continues to be a need in developing improved stents and stent delivery systems.
The present invention offers a stent and system having a space-efficient mode of stent delivery.